1. Field of the Invention
This invention relates to an apparatus for inspecting both sides of a tape or a sheet.
This invention is applicable to an apparatus that magnifies and visually inspects both sides of a transparent, translucent or opaque tape or sheet, such as a TAB tape and a flexible printed-circuit board.
2. Description of the Related Art
Tape automated bonding (TAB) is one of the automatic bonding processes for semiconductor devices. In TAB, a semiconductor chip is attached, bonded and sealed on each frame of a long TAB tape (U.S. Pat. No. 4,827,376 V. V. Scott). A TAB tape is made of transparent or translucent plastics, such as polyimide, with a large number of extra-fine wires of copper or gold- or tin-plated copper laid on the surface.
Before attaching semiconductor devices, each TAB tape is inspected for defects. Each frame of a TAB tape, intermittently paid off from a reel, is visually inspected under a microscope for broken leads, deformation and other defects.
Two-side wired TAB tapes must be inspected on both sides.
With the conventional inspection apparatus, however, one side of a tape is first inspected throughout. Then, the tape is reversed for the inspection of the other side. Namely, the TAB tape passes through the inspection apparatus twice. This has decreased the efficiency of the inspection work, increased chances of damaging the TAB tape and lowered the production yield.
Similar problems have been encountered in the two-side inspection of flexible printed-circuit board, as well.